Refactored int/uint range code in preparation for change to range_rev semantics.

Also added unit tests of range code to test refactoring.  The
num-range-rev.rs test will need to be updated when the range_rev
semantics change.

2 files changed, 233 insertions, 0 deletions

diff --git a/src/test/run-pass/num-range-rev.rs b/src/test/run-pass/num-range-rev.rs
new file mode 100644
index 00000000000..e65c793a7b4
--- /dev/null
+++ b/src/test/run-pass/num-range-rev.rs
@@ -0,0 +1,114 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use std::int;
+use std::uint;
+
+fn uint_range(lo: uint, hi: uint, it: &fn(uint) -> bool) -> bool {
+    uint::range(lo, hi, it)
+}
+
+fn int_range(lo: int,  hi: int, it: &fn(int) -> bool) -> bool {
+    int::range(lo, hi, it)
+}
+
+fn uint_range_rev(hi: uint, lo: uint, it: &fn(uint) -> bool) -> bool {
+    uint::range_rev(hi, lo, it)
+}
+
+fn int_range_rev(hi: int,  lo: int, it: &fn(int) -> bool) -> bool {
+    int::range_rev(hi, lo, it)
+}
+
+fn int_range_step(a: int, b: int, step: int, it: &fn(int) -> bool) -> bool {
+    int::range_step(a, b, step, it)
+}
+
+fn uint_range_step(a: uint, b: uint, step: int, it: &fn(uint) -> bool) -> bool {
+    uint::range_step(a, b, step, it)
+}
+
+
+pub fn main() {
+    // int and uint have same result for
+    //   Sum{100 > i >= 2} == (Sum{1 <= i <= 99} - 1) == n*(n+1)/2 - 1 for n=99
+    let mut sum = 0u;
+    for uint_range_rev(99, 1) |i| {
+        sum += i;
+    }
+    assert_eq!(sum, 4949);
+
+    let mut sum = 0i;
+    for int_range_rev(99, 1) |i| {
+        sum += i;
+    }
+    assert_eq!(sum, 4949);
+
+
+    // elements are visited in correct order
+    let primes = [2,3,5,7,11];
+    let mut prod = 1i;
+    for uint_range_rev(4, 0) |i| {
+        println(fmt!("uint 4 downto 0: %u", i));
+        prod *= int::pow(primes[i], i);
+    }
+    assert_eq!(prod, 11*11*11*11*7*7*7*5*5*3);
+    let mut prod = 1i;
+    for int_range_rev(4, 0) |i| {
+        println(fmt!("int 4 downto 0: %d", i));
+        prod *= int::pow(primes[i], i as uint);
+    }
+    assert_eq!(prod, 11*11*11*11*7*7*7*5*5*3);
+
+
+    // range and range_rev are symmetric.
+    let mut sum_up = 0u;
+    for uint_range(10, 30) |i| {
+        sum_up += i;
+    }
+    let mut sum_down = 0u;
+    for uint_range_rev(29, 9) |i| {
+        sum_down += i;
+    }
+    assert_eq!(sum_up, sum_down);
+
+    let mut sum_up = 0;
+    for int_range(-20, 10) |i| {
+        sum_up += i;
+    }
+    let mut sum_down = 0;
+    for int_range_rev(9, -21) |i| {
+        sum_down += i;
+    }
+    assert_eq!(sum_up, sum_down);
+
+
+    // empty ranges
+    for int_range_rev(10, 10) |_| {
+        fail!("range should be empty when start == stop");
+    }
+
+    for uint_range_rev(0, 1) |_| {
+        // fail!("range should be empty when start-1 underflows");
+    }
+
+    // range iterations do not wrap/underflow
+    let mut uflo_loop_visited = ~[];
+    for int_range_step(int::min_value+15, int::min_value, -4) |x| {
+        uflo_loop_visited.push(x - int::min_value);
+    }
+    assert_eq!(uflo_loop_visited, ~[15, 11, 7, 3]);
+
+    let mut uflo_loop_visited = ~[];
+    for uint_range_step(uint::min_value+15, uint::min_value, -4) |x| {
+        uflo_loop_visited.push(x - uint::min_value);
+    }
+    assert_eq!(uflo_loop_visited, ~[15, 11, 7, 3]);
+}
diff --git a/src/test/run-pass/num-range.rs b/src/test/run-pass/num-range.rs
new file mode 100644
index 00000000000..7c1f905a049
--- /dev/null
+++ b/src/test/run-pass/num-range.rs
@@ -0,0 +1,119 @@
+// Copyright 2013 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+use std::int;
+use std::uint;
+
+fn uint_range(lo: uint, hi: uint, it: &fn(uint) -> bool) -> bool {
+    uint::range(lo, hi, it)
+}
+
+fn int_range(lo: int, hi: int, it: &fn(int) -> bool) -> bool {
+    int::range(lo, hi, it)
+}
+
+fn int_range_step(a: int, b: int, step: int, it: &fn(int) -> bool) -> bool {
+    int::range_step(a, b, step, it)
+}
+
+fn uint_range_step(a: uint, b: uint, s: int, it: &fn(uint) -> bool) -> bool {
+    uint::range_step(a, b, s, it)
+}
+
+pub fn main() {
+    println(fmt!("num-range start"));
+    // int and uint have same result for
+    //   Sum{2 <= i < 100} == (Sum{1 <= i <= 99} - 1) == n*(n+1)/2 - 1 for n=99
+    let mut sum = 0u;
+    for uint_range(2, 100) |i| {
+        sum += i;
+    }
+    assert_eq!(sum, 4949);
+
+    let mut sum = 0i;
+    for int_range(2, 100) |i| {
+        sum += i;
+    }
+    assert_eq!(sum, 4949);
+
+
+    // elements are visited in correct order
+    let primes = [2,3,5,7];
+    let mut prod = 1i;
+    for uint_range(0, 4) |i| {
+        prod *= int::pow(primes[i], i);
+    }
+    assert_eq!(prod, 1*3*5*5*7*7*7);
+    let mut prod = 1i;
+    for int_range(0, 4) |i| {
+        prod *= int::pow(primes[i], i as uint);
+    }
+    assert_eq!(prod, 1*3*5*5*7*7*7);
+
+
+    // empty ranges
+    for int_range(10, 10) |_| {
+        fail!("range should be empty when start == stop");
+    }
+
+    for uint_range(10, 10) |_| {
+        fail!("range should be empty when start == stop");
+    }
+
+
+    // range iterations do not wrap/overflow
+    let mut oflo_loop_visited = ~[];
+    for uint_range_step(uint::max_value-15, uint::max_value, 4) |x| {
+        oflo_loop_visited.push(uint::max_value - x);
+    }
+    assert_eq!(oflo_loop_visited, ~[15, 11, 7, 3]);
+
+    let mut oflo_loop_visited = ~[];
+    for int_range_step(int::max_value-15, int::max_value, 4) |x| {
+        oflo_loop_visited.push(int::max_value - x);
+    }
+    assert_eq!(oflo_loop_visited, ~[15, 11, 7, 3]);
+
+
+    // range_step never passes nor visits the stop element
+    for int_range_step(0, 21, 3) |x| {
+        assert!(x < 21);
+    }
+
+    // range_step_inclusive will never pass stop element, and may skip it.
+    let mut saw21 = false;
+    for uint::range_step_inclusive(0, 21, 4) |x| {
+        assert!(x <= 21);
+        if x == 21 { saw21 = true; }
+    }
+    assert!(!saw21);
+    let mut saw21 = false;
+    for int::range_step_inclusive(0, 21, 4) |x| {
+        assert!(x <= 21);
+        if x == 21 { saw21 = true; }
+    }
+    assert!(!saw21);
+
+    // range_step_inclusive will never pass stop element, but may visit it.
+    let mut saw21 = false;
+    for uint::range_step_inclusive(0, 21, 3) |x| {
+        assert!(x <= 21);
+        println(fmt!("saw: %u", x));
+        if x == 21 { saw21 = true; }
+    }
+    assert!(saw21);
+    let mut saw21 = false;
+    for int::range_step_inclusive(0, 21, 3) |x| {
+        assert!(x <= 21);
+        if x == 21 { saw21 = true; }
+    }
+    assert!(saw21);
+
+}